Straight feed press

ABSTRACT

A sheet-fed lithographic offset printing press in which sheets are aerodynamically supported and directed in a single horizontal plane straight to and through individually driven and mechanically synchronized multi-color perfecting towers while the sheet is continuously gripped and moved by a single set of grippers at the leading edge so that only blanket printing cylinders touch the sheet, eliminating sheet transfer between the time the sheet leaves the feeder and the time it reaches the delivery.

United States Patent Dahlgren [45] May 23, 1972 STRAIGHT FEED PRESS [72] Inventor: Herold P. Dlltlgren, 726 Regal Row, Dallas, Tex. 75247 [22] Filed: June 17, 1968 [21] App1.No.: 737,521

[52] US. Cl ..101/l77, 101/184, 101/232, 101/229 [51] Int. Cl. ..B4lI7/l2,B41f7/04 [58] FleldolSe-reh ..101/l36,l74,175,177,216,

[56] References Cited UNITED STATES PATENTS 2,551,060 5/1951 Simmons 101/232 2,753,798 7/1956 Babst 101/232 2,794,390 6/1957 Burke 101/232 3,422,757 l/1969 Grobman et a1 ..101/232 1,348,253 8/1920 Uphnm ..101/23l 2,138,405 11/1938 ....101/183 3,179,404 4/1965 Felts et a1. ..271/79 3,196,788 7/1965 Knowles ..l0l/2l7 3,221,651 12/1965 Tagliasaechi. ....101/183 3,351,394 11/1967 Hooker ..308/9 Primary Examiner-Wil1iam 8. Penn Assistant ExaminerE. M. Goven Alt0mey-Howard E. Moore ABSTRACT A sheet-fed lithographic offset printing press in which sheets are aerodynamically supported and directed in a single horizontal plane straight to and through individually driven and mechanically synchronized multi-color perfecting towers while the sheet is continuously gripped and moved by a single set of grippers at the leading edge so that only blanket printing cylinders touch the sheet, eliminating sheet transfer between the time the sheet leaves the feeder and the time it reaches the delivery.

45Clahm,28DrowingFigures Patented May 23, 1972 INVENTOR ATTORNEY l5 Sheets-Sheet 1 Patented May 23, 1972 15 Sheets-Sheet 2 INVENTOR 191915 05 019 7565 5 BY M E I M ATTORNEY Patented May 23, 1972 3,664,261

15 Sheets-Sheet Ls HEPJLD I? DQ525195 ATTORNEY Patented May 23, 1972 3,664,261

15 Sheets-Sheet 4 INVENTOR W M w 1 9 ATTORNEY Patented May 23, 1972 3,664,261

15 Sheets-Sheet 5 Maw 19019152619677 ATTORNEY Patented May 23, 1 972 3,664,261

15 Sheets-Sheet 6 3& BY M 87W ATTORNEY Patented May 23, 1972 3,664,261

15 Sheets-Sheet '7 a E W A 2249 2.24

INVENTOR 6 19/9069 I. Dflf/LFAi/V ATTORNEY Patented May 23, 1972 IEFJ I kf in INVENT OR ATTORNEY INVENTOR 1 M w m M H. 0 3 P 0 L m 9 W M W 5 1E w mm mm t m mum s w 11 HI! w mm M v 2 1 7 '1 w :1 a mm w 3 2 mwn n; mun wt in W L1 M km w Q: Qm m n w m m mm a? P m ww ATTORNEY Patented May 23, 1972 3,664,261

15 Sheets-Sheet 1O H54 7 EXCHANGE/Q INVENTOR ll/YA'JM P Bil/615 5 BY W E ATTORNEY Patented May 23, 1972 3,664,261

15 Sheets-Sheet 11 BY W 'M ATTORNEY Patented May 23, 1972 15 Sheets-Sheet 1 2 ww r LJINVENTOR 55mm 5.00am? B M Z M ATTORNEY INVENTOR ATTORNEY Patented May 23, 1972 15 Sheets-Sheet 1L,

Patented May 23, 1972 3,664,261

15 Sheets-Sheet l5 fill/PHD F EMF/PM BY Mg ATTORNEY STRAIGHT FEED PRESS BACKGROUND OF THE INVENTION No significant advances have been made presenting new concepts in sheet-fed printing systems for decades. Printing systems designed for the sheet-fed printer are basically the same and allow printing on one side of the sheet at a time, requiring sheets to be turned over and rerouted through the press for single or multi-color perfecting. Sheets are progressively and meticulously transferred in serpentine fashion about transfer and impression cylinders and hopefully registered from one cylinder to another and from one printing unit to another until finally they emerge as a printed product. Printing units must be synchronized for color register through numerous drive and idler gears and consequently presses are extremely complex, massive units which are very expensive to manufacture because of numerous transfer and printing cylintiers and mechanisms related thereto.

One or two color sheet-fed perfectors have been developed heretofore. However, these machines were specifically designed for specific jobs, such as mass production of paperback books, and are totally unsuitable for high-speed production of four-color process printing on both sides of the paper.

Heretofore no sheet-fed press had the capability of printing on two sides of a sheet in as many as four colors by passing the paper through the press one time.

lt is the common and accepted practice in the printing industry to run a sheet to be printed through the sheet-fed press a multiplicity of times to attain multi-color printing on two sides ofa sheet. After each pass of the sheet through the press, the plates must be changed and the press made ready for the next pass to apply other colors or to print on the back of the sheet. It is readily apparent to those skilled in the printing art that a considerable amount of time is spent making sheet-fed presses ready to print and in attaining proper registry of the numerous components of the press.

In a typical four-color one-side printing press a sheet delivered from the feeder is caught by the gripper bars of a first transfer cylinder. The sheet is folded around the transfer cylinder and carried to the grippers on the first impression cylinder where the grippers of the transfer cylinder release the paper and it is caught by the grippers of the impression cylinder. The grippers on the impression cylinder rotate the paper into contact with the blanket cylinder where printing is accomplished in one color on one side of the sheet. When the grippers on the the impression cylinder release the sheet, grippers on a second transfer cylinder grasp the sheet, causing the printed surface to he in contact with the transfer cylinder while it is rotated to the grippers of a second impression cylinder. The grippers of the second transfer cylinder release the sheet as it is caught by the grippers of the second impression cylinder which rotates the sheet into contact with a second blanket where a second color is applied to the same side of the sheet. Grippers on a third transfer roller catch the sheet as it is released by the grippers of the second impression cylinder and the printed surface is again brought into contact with a transfer cylinder while it is being delivered to the grippers of a third impression cylinder. This process is continued until the sheet passes to delivery. When one side ofthe sheet is completed, the press is replated, the sheets are turned and refed through the press to print the other side of the sheet.

Virtually all sheet-fed printing presses heretofore developed have the characteristic of feeding the sheet serpentine fashion through the press while the grippers associated with each cylinder catch the sheet as it is being released by the grippers of the previous cylinder.

One of the major problems encountered by the printing industry lies in synchronizing the various cylinders whereby the sheet will be grasped and released at the proper moment for maintaining registry between the cylinders of successive towers so that colors do not overlap or separate.

Chains have been used in the past with limited success to transfer sheets from one printing station to another. Grippers supported by the chain have to be positively indexed to the printing station cylinders before sheet transfer can be accomplished with any degree of register between stations.

A chain has inherent limitations as a smooth transfer media because chordal motion of the links limit smooth flow; linear deformation of the chain results from numerous pivot joints; lubrication requirements at joints, to help prevent wear, noise, shock and vibration, present maintenance problems.

The gripper and chain transfer media could not, by itself, register the sheet between printing stations, even with the chain travelling precisely at cylinder speeds. As a compromise, grippers had to be loosely supported on the chain, moved from normal position, and indexed to printing station cylinders prior to actual sheet transfer at the cylinder. As soon as sheet transfer was accomplished and the gripper became separated from index with the cylinder, the gripper jumped or jerked back into its normal relation with the chain.

In the transfer system employed and disclosed herein, there is no contact between tape directed gripper bars and the printing cylinders thereby eliminating shock, vibration, wear, noise, mis-register and other apparent problems accompanied by chain supported grippers being indexed to cylinders. The printing cylinders are entirely independent of the sheet transfer mechanism and vice versa except for speed synchronization of cylinder surface speed with that of the tape.

Another problem has been the offsetting of wet ink on transfer cylinders from the freshly printed surface on the paper and consequently back on to the next sheet that is passed through the press. Heretofore, presses with a multiplicity of towers for applying more than one color of ink to the sheet were driven by a common drive through a complex gear train or through long shafts which have inherent distortion thereby increasing the problem of synchronizing components of the press thereby making precision registry more difficult.

Typical four-color one-side printing presses have an average of about 20 cylinders including the plate cylinders, blanket cylinders, impression cylinders, transfer cylinders and skeleton wheels.

Sheet-fed printing presses heretofore used have relatively low production speeds which never exceed 8,000 impressions per hour.

All sheet-fed presses heretofore used have basically the same complex ink fountain with keys to vary the ink flow and an ink train consisting on an average of about twenty rollers for smoothing and distributing the ink to the plate cylinder.

A universal characteristic of sheet-fed printing presses heretofore used has been the employment of massive bearers on each end of the plate and blanket cylinders to assure rotation of the cylinders without vibration when the cylinder load is reduced because of gaps in the cylinders. The use of bearers has been necessitated by limitations of bearings heretofore incorporated into the design of presses for journaling the cylinders.

Apart from the equipment design being basically the same, one only has to be briefly associated with problems in the industry to see that printing problems, too, are the same for the similarly designed presses; namely, extensive time and effort are required for make-ready; extreme difficulty in obtaining and maintaining register between colors; streaking and slur caused by gear lash and deformation or by vibration and shock of complex mechanism movements; offsetting caused by the printed side of the sheet being in contact with transfer cylinder and skeleton wheel surfaces; sheet or board fatigue; considerable downtime for maintenance caused by breakdown of the complex mechanical systems; problems relating to ghosting on certain printing layouts; problems relating to control of ink-water balance and sometimes the most neglected problem of all, that of requiring personnel having special skills, talents, experience and perseverance to "get the job done with the above mentioned type of printing systems.

All the above problems are related basically to problems involving lack of versatility, quality, economy and ease of operation, and are largely caused by the stereotype conventional design of the present day printing system.

Since the problems for the sheet-fed printer are not being readily solved by "updating and face-lifting" of the old concepts of printing, the only apparent alternative has been to switch to web-offset lithography. Here the printer can print several colors on two sides of the sheet at the same time with increased production. In addition to the multi-color perfecting capability the web-press is superior to the sheet-fed press in specific situations because higher production rates and lower break-even points are possible.

This at first would seem to be the answer, except for the fact that many of the problems existing in sheet-fed printing also exist in web-offset; namely, lack of color register caused by deformation of long drive shafts; basically the same kind ofink fountain with keys used in sheet-fed presses; a complicated train of rollers and conventional water fountain systems; common drive for the entire press; roller or ball-bearings with massive cylinder bearers on the plate and blanket cylinders; and printing cylinders are universally the same circumference as the finished sheet cut'off length, allowing absolutely no time for recovery of the inking form rollers after they finish a print ing cycle.

Apart from problems common to the conventional sheetfed operation, switching from sheet fed to web-offset lithography presents other distinct disadvantages.

A web-offset press is limited to one sheet length equal to the circumference of the plate cylinder. When shorter sheet lengths are required excessive waste results from non-use of the unprinted web portion. Another complete press system must be designed, manufactured, purchased and used for printing different sheet sizes to avoid excessive waste of paper. Web presses are generally more expensive because of complex folders, dryers, chill devices, etc., necessary. More time is usually required for make-ready and more waste is encountered since the web must be running through the press and desirably at production speeds while registering and while color correction changes are being made because it is difficult to compensate for wind-up of the drive system when the press is stopped. Crews trained for printing on sheet-fed equipment find that they must learn new skills when using web equipment.

The printing industry is faced with a dilemma of the sheetfed and web-fed printing operations, each having decided advantages over the other, while sharing common problems which are inherent in the stereotyped press design which has been virtually unchanged for decades.

SUMMARY OF THE INVENTION l have developed a novel sheet-fed offset lithographic printing press which incorporates the advantages of sheet-fed equipment heretofore employed and the advantages of the web-press, while eliminating deficiencies of each.

By eliminating elements which did not contribute to the success of the lithographic printing press but which prevented or defeated it, I have developed a sheet-fed printing press which has the capability of perfecting, i.e., printing on both sides of the sheet at the same time, in any desired number of colors while the sheet is passed one time through the printing press.

I have eliminated all transfer cylinders, impression cylinders and skeleton sheets which have been used heretofore for feeding a sheet through the press serpentine fashion.

I have developed a sheet-fed printing press which incorporates a straight through and continuous sheet transfer principle similar to the feeding style of a web press whereby the sheet is grasped by a gripper bar after being delivered to the sheet transfer mechanism by a conventional feeder and the sheet is directed in an uninterrupted horizontal plane straight to and through one or a plurality of printing towers where printing is accomplished selectively on one side; or, on both sides of the sheet at the same instant, or any combination thereof in any desired number of colors. This eliminates tuming the sheet over after printing on one side and re-feeding it through the printing system. This also eliminates the necessity for numerous cylinders, constantly gripping and releasing the sheet as has been required heretofore.

Eliminating the complex ink fountain used on conventional presses, l have developed a press with a novel ink fountain, having a rigid doctor blade and a minimum number of rollers in the ink train for applying ink to the plate cylinder.

l have eliminated the need for bearers on the blanket and plate cylinders by the use of a novel journal, which has not been used heretofore in printing presses, which operates on hydrostatic principles offering a new and unexpected result, in that it eliminates the need for bearers.

l have eliminated the common drive system and have incorporated a novel system for driving the printing towers by individual drive motors while maintaining register for multicolor printing by the use of synchronizing links for maintaining critical elements of each printing tower and the sheet transfer system in synchronization at all times.

It is a primary object of the invention to provide a sheet-fed printing press which incorporates a sheet transfer system which moves the sheet in virtually a straight horizontal line, eliminating transfer and impression cylinders, in which the sheet length is unrelated to and may be variably less than the circumference of the printing cylinder, thereby incorporating the straight feed characteristic of the web press with the variable cut-off characteristic of the sheet-fed press.

Another object of the invention is to provide a sheet-fed press in which the sheet is continuously gripped by a single set of grippers from the time the sheet enters the press until delivery, offering the ultimate in register for multi-color printmg.

Another object of the invention is to provide a printing press in which the sheet is grasped at the leading edge by a set of grippers and aerodynamically supported and directed to and through one or more printing towers.

A further object of the invention is to provide a sheet-fed printing press which may be used as a perfector to print any desired number of colors on both sides of the sheet, eliminating the need for a second pass through the press.

A still further object of the invention is to provide a sheet transfer system capable of gripping and registering two sheets simultaneously in a single set of grippers to move the sheets through perfecting printing towers to print on one side of each sheet.

A further object of the invention is to provide a printing press in which the only cylinders which touch the paper are the blanket printing cylinders, thereby eliminating all costly transfer cylinders, impression cylinders, skeleton wheels, and related complex gripper mechanisms commonly used in sheetfed presses.

A further object of the present invention is to eliminate marking caused by the offsetting of wet ink on sheets exposed to transfer cylinders and subsequent ofi'setting of the ink to subsequent sheets.

A still further object of the invention is to provide a sheetfed printing press having a sheet gripping mechanism carried by an endless flexible conveyor having an in-line feeder and delivery, allowing fast but accurate control of the speed of the paper through the press.

A still further object of the invention is to provide a sheetfed printing press in which the sheet travels through the path of least resistance thereby utilizing natural phenomena such as the cantilever effect on the sheet as it is grasped in the nip between the blanket cylinders, causing the sheet to lie tangent to the blanket cylinders due to its modulus of elasticity and also phenomena involving boundary layers of air and air pressure at the nip between opposing blanket cylinders.

A still further object of the invention is to provide a printing press having a simplified continuous inking and dampening system, eliminating problems relating to ink-water balance, emulsification, ghosting, one turn roller streaks and hickies".

A still further object of the invention is to provide a printing press having a novel plate cylinder having a printing plate covering approximately one-half of the circumference thereof and an ink receptive recovery plate covering substantially the other half thereof associated with the ink train, allowing recovery time for redistribution of the ink on the form rollers of the ink train to eliminate ghosting.

Another object is to provide a printing press having an ink fountain which does not supply an overabundance of ink to the inking form rollers while the form rollers are in the plate cylinder gap, thereby eliminating one turn roller streak.

A still further object of the invention is to provide a printing press having an ink fountain utilizing a rigid doctor blade in contact with a resilient roller wherein the thickness of the ink film to be applied may be metered continuously and applied at a controlled, uniform rate in regulated quantities as demanded by the printing layout.

A still further object of the invention is to provide a sheetfed printing press which may serve as a perfector in which printing is achieved on both sides of the sheet at precisely the same moment as the sheet is drawn between adjacent blanket cylinders and touches the cylinders only at the printing nip.

A still further object of the invention is to provide a sheetfed printing press in which each blanket cylinder serves the dual purpose of a blanket cylinder for offsetting ink to the sheet and simultaneously as an impression cylinder for the blanket which is offsetting ink to the opposite side of the sheet.

These and other objects are effected by my invention as will be apparent in the following description taken in conjunction with the accompanying drawings.

DESCRIPTION OF THE DRAWING The accompanying drawings illustrating the present invention are provided so that the invention may be better and more fully understood, in which:

FIG. I is a side elevational view of the operator side of the printing press;

FIG. II is a top plan view of the printing press having the inker broken away;

FIG. III is a side elevational view of the drive side of the printing press;

FIG. IV is a cross sectional view taken along lines IV-IV of FIG. II;

FIG. V is a sectional view through a typical printing tower taken along lines V-V of FIG. ll;

FIG. VI is a cross sectional view taken along lines VIVI of FIG. Il showing a typical tape wheel in the delivery station;

FIG. VII is an enlarged elevational view of a typical gripper bar looking in the direction indicated by the arrows along lines VIIVII ofFIG. II;

FIG. VIII is a cross sectional view taken along lines VIII- VIII of FIG. VII through atypical gripper bar with the gripper in closed position;

FIG. IX is a cross sectional view taken along lines IX-IX of FIG. II through a typical gripper bar with the gripper in the open position at the delivery station;

FIG. X is a cross sectional view taken long lines XX of FIG. I showing the details of construction of the sheet transfer mechanism at the delivery station;

FIG. XI is a partially sectionalized fragmentary view illustrating the details of construction and mounting of a typical plate cylinder;

FIG. XII is a partially sectionalized fragmentary view illustrating details of construction and mounting of the upper blanket cylinder;

FIG. XIII is a diagrammatic view illustrating a suitable hydraulic circuit for providing lubrication to the hydrostatic bearing bearers utilized for journaling the plate and blanket cylinders;

FIG. XIV is an enlarged cross sectional view taken along lines XlV-XIV of FIG. XIII;

FIG. XV is a perspective view of a portion of a hydrostatic bearer illustrating a suitable configuration of a recess utilized for receiving lubricant for the bearing;

FIG. XVI is a perspective view of a portion of a hydrostatic bearer illustrating a suitable configuration of the annular rings utilized for draining lubricant from the bearing;

FIGS. XVII, XVIII and XIX illustrate the relationship between the blanket cylinders and the gripper bar assembly which continuously grips the sheet as the gripper bar assembly and sheet enter (FIG. XVII), pass through (FIG. XVIII) and leave (FIG. XIX) the cutaway portion of respective blanket cylinders;

FIG. XX is an enlarged cross sectional view illustrating the nip between opposing blanket cylinders while printing is being accomplished on a sheet;

FIG. XXI is a partially sectionalized fragmentary view illustrating details of construction and mounting of the lower blanket cylinder;

FIG. XXII is an enlarged cross sectional elevational view cut transversely through the rollers of the upper ink train;

FIG. XXIII is a cross sectional view taken along lines XXIII-XXIII of FIG. XXII;

FIG. XXIV is a cross sectional view taken along lines XXIVXXIV of FIG. XXII:

FIG. XXV is a cross sectional view taken along lines XXV- XXV of FIG. XXII illustrating details of construction of the primary inker;

FIG. XXVI is an enlarged cross sectional view, similar to FIG. XXII, ofa second embodiment of the primary inker;

FIG. XXVII is an elevational view, with parts broken away, of a crankplate in the synchronizing system;

FIG. XXVIII is a cross sectional view taken along lines XX- VIll-XXVIII of FIG. XXVII.

Numeral references are employed to indicate the various parts as shown in the drawings and like numerals indicate like parts throughout the various figures of the drawing.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to FIG. I of the drawings the numeral I generally designates a sheet-fed multi-color perfecting lithographic printing press.

A feeder mechanism 2 feeds sheets of unprinted paper from a stack 4 by conventional means to a swing gripper 6. The swing gripper 6 accelerates individual sheets 5 to the velocity of gripper bars 8 carried by the sheet transfer mechanism, generally designated by the numeral 10. Sheet transfer mechanism 10 consists of tape wheels 12a, 12b and 14a, 14b which carry tapes 16a and 16b, having gripper bars 8 mounted therebetween for moving individual sheets 5 through the printing press, as will be hereinafter more fully described.

A plurality of printing towers I8 and 20 is provided, giving the press a multi-color perfecting capability. Conventional leveling devices such as jack screws (not shown) may be utilized for tower leveling.

A delivery mechanism 22 grips the individual sheets 5 as they are released by gripper bars 8 of the sheet transfer mechanism 10 and positions the sheets by conventional means in a stack of printed sheets 24.

Referring to FIGS. II and V of the drawing, each printing tower l8 and 20 has a side frame 26 on the operator side and side frame 28 on the drive side of the printing press joined by tie bars 30 forming a strong rigid structure upon which various components of the press are mounted. Feeder 2 and delivery 22 have operator-side side frames 2a and 22a and drive-side side frames 2b and 22b respectively. Structural ties 31 join the side frames of individual towers 18 and 20 and side frames of the feeder 2 and delivery 22.

Primary inkers 32 and secondary inkers 34 cooperate with dampeners 36 to provide a proper balance of ink and dampening fluid to the plate cylinders 38, which are duplicated at the upper and lower ends of the tower.

PLATE CYLINDER Plate cylinders 38, FIGS. V and XI, are rotatably journaled at opposite ends thereof in side frames 26 and 28 in bearings 27 and 29. It should be noted that plate cylinders 38 differ from conventional plate cylinders in two very important aspects.

First, the printing plate 40 does not cover substantially all of the circumference of plate cylinder 38, FIG. V. Printing plate 40 wraps around substantially one-half of the circumference of plate cylinder 38.

Both web and sheet-fed presses heretofore developed have covered as much of the surface of the plate cylinder as possible with the plate. This has been necessitated in web presses to reduce waste of paper and in the sheet-fed presses to make a more compact press.

Plate 40 is detachably secured to plate cylinder 38 by conventional plate clamps 42 conventionally positioned in gap 39. An ink pad 44 is mounted in a similar manner as plate 40 and covers substantially the remaining circumference of plate cylinder 38.

Ink pad 44 is an ink receptive plate having an effective diameter slightly greater than that of the effective diameter of the plate 40. In view of the fact that the surface of the ink pad 44 is of greater radial distance from the center of the plate cylinder 38 than the radial distance from the center of the plate cylinder to the surface of plate 40, ink is distributed over ink pad 44 by primary inker 32 and the ink is spread over the form rollers of the secondary inker 34 from pad 44, while plate 40 does not contact rollers of the primary inker but receives ink only from the form rollers of the secondary inker.

Utilization of the ink pad 44 allows great simplification of the conventional ink train, while overcoming ghosting problems often encountered by lithographers using conventional inking systems. Since plate 40 does not cover the substantial circumference of plate cylinder 38, form rollers in the ink fountain have sufiicient time to recover, eliminating ghosting as will be hereinafter described.

The second important deviation of plate cylinder 38 from the conventional plate cylinder is the elimination of bearers. Bearers have been universally used on plate cylinders and blanket cylinders to prevent vibration when cutaway portions of the plate cylinder and blanket cylinder come into rolling contact.

Plate cylinder 38 has reduced diameters at opposite ends thereof, forming journals 38a and 38b which are supported by bearings 27 and 29 respectively in the side frames 26 and 28. One end 380 of plate cylinder 38 is captured by the lateral register adjustment 58, as will be hereinafter explained, while the other end 38b is free to slide axially through bearing 29. This construction provides automatic compensation for ther mal expansion of plate cylinder 38.

I have eliminated the need for bearers by replacing conventional hall, sleeve and roller bearings with a hydrostatic bearer 46, FIGS. XI-XVI, which is machined to very close tolerance between bearing sleeve 27 and 29 and journals 38a and 38/7 on the plate cylinders 38 and journals 48a and 48b on blanket cylinders 48, allowing virtually no vibration of the plate cylinder as will be hereinafter more fully explained.

BLANKET CYLINDER When printing is being accomplished blanket cylinders 48 are in rolling contact with plates 40 on plate cylinders 38, FIG. V. On each upper and lower unit, blanket 50 is detachably secured to blanket cylinder 48 by conventional blanket clamps 52 and is of substantially the same length as plate 40, thereby covering the same proportion of the circumference of blanket cylinder 48 as plate 40 covers on plate cylinder 38 which is equal in diameter to blanket cylinder 48. Each blanket cylinder 48 has a recessed area 54 on the outer surface, providing clearance for the ink pad 44 on plate cylinder 38 to prevent contact between the blanket cylinder 48 and the ink pad 44.

It should be noted that as hereinbefore explained that blanket cylinders 48 do not have conventional bearers on each end thereof, but each blanket cylinder 4! has a journal 48a and 48b at opposite ends thereof supported in hydrostatic bearings 46 which will be described in detail hereinafter.

Each blanket cylinder 48 has a recessed gap or cutaway portion 56 on the outer surface. FIGS. V, XVII, XVIII and XIX, allowing gripper bars 8 to move therebetween as they rotate. Referring to FIGS. II, IV, V and XXI, it should be noted that each blanket or printing cylinder 48U and 48L has reduced diameter areas adjacent each end thereof. Tracks 224 and 226 and flexible conveyors 16a and 16b extend through openings between the cylinders formed by the reduced diameter areas. Gripper bars 8 enter gaps 56 and conveyors 16a and 16b move freely along an unobstructed path between the printing cylinden 48 and 48L in non-engaging, non-driving relationship with the cylinders.

ADJUSTMENT AND THROW OFF Each plate cylinder 38 has conventional lateral color registering adjustment mechanism 58, FIG. I and XI. A suitable means for establishing and maintaining lateral register comprises a worm 58a and a worm gear 58b for driving a spur gear 580 which in turn meshes with gear teeth on a threaded adjustment screw 58d whereby rotation of the worm 580 will cause the threaded adjustment screw 58d to be moved laterally, thereby moving plate cylinder 38 laterally with respect to the side frames 26 and 28. Adjusting screw 58d threadedly engages collar S8e, rigidly connected to the operator-side side frame 26 by bolts 58]". Adjusting screw 58d has annular thrust bearing 58g mounted therein which is captured between shoulders 38c on cylinder 38 and plate 58h secured by bolts 58: to the end of plate cylinder journal 38a.

A throw-off mechanism is utilized to separate the blanket cylinders 48U and 48L from plate cylinders 38U and 381. respectively and to separate the upper blanket cylinder 48U from lower blanket cylinder 48L when the last sheet passes from the feeder or when a sheet 5 fails to feed. A suitable mechanism, FIGS. I and V, comprises a throw-off hydraulic cylinder 60 actuated by an electric eye or other suitable means (not shown), pivotally connected to a crank 62 wherein actuation of throw-off cylinder 60 causes crank 62, which is rigidly connected to cross shaft 64, to rotate shaft 64. Crank 62, rigidly connected to shaft 64, also moves adjustable link 70 to rotate a second crank 72 rigidly secured to a second cross shaft 74. Rotation of the first and second cross shafts 64 and 74 respectively results in rotation of cranks 76 which are rigidly secured to each of said cross shafts. A rod eye 78 is pivotally connected to each crank 76 and has an adjustment screw 82 threadedly engaged therein. Screw 82 extends through and threadedly engages pin 82b and is secured relative thereto by lock nuts 82c and 82d threadedly engaging adjustment screw 82. Pin 82b, FIGS. XII and XXI, is rotatably journaled in bushings 82e, rigidly connected to outwardly extending lugs 800 on throw-off crank 80. Throw-off crank is rigidly connected to eccentric bushing 27a and 29a of hydrostatic bearing 46. The eccentricity of bushings 27a and 290 causes opposing blanket cylinders 48L and 48U to move to an off impression position when throw-ofi cylinder 60 is actuated. It should be apparent that actuation of throw-off cylinder 60 results in rotation of throw-off crank 80 and ec centric bushings 27a and 29a, causing each blanket cylinder 48U and 48L to move from contact with plate cylinders 38U and 38L respectively and causes blanket cylinders 48U and 48L to be separated.

Paper pressure adjustment 84, FIGS. I, V and XXI, consists of a worm 84a rotatably mounted on the operator-side side frame 26, which rotates a worm gear segment rigidly connected to cross shaft 84b, transmitting rotation to lever arm 84c rigidly connected to cross shaft 84b. An adjustable rod 84a is pivotally connected between lever arm 84c and the paper pressure eccentric 84c. 

1. In a sheet-fed printing press, a feeder station; a delivery station; at least one cylinder support, including spaced side members intermediate the feeder and delivery stations; a printing cylinder journaled between the side members; an impression cylinder adjacent the printing cylinder, at least one of said cylinders having a gap formed therein and extending longitudinally thereof to allow passage of a gripper member between said cylinders; means for applying ink to the printing cylinder; continuous flexible sheet transfer means movably extending from the feeder station to the delivery station; means to drive the sheet transfer means at a preselected constant speed; gripper members carried by the sheet transfer means adapted to receive and grip the edge of a sheet at the feeder station and continuously convey same to the delivery station; carrier guide means adjacent opposite sides of the press to direct the gripper members along a substantially straight path between opposite ends of the press; power transmission means to rotate the said cylinders at a pre-selected constant speed; and synchronizing means secured to the power transmission means and to the means to drive the sheet transfer means to cause the sheet transfer means and the printing cylinder to move in a selected unchanging speed relationship.
 2. In a sheet-fed printing press, a feeder station; a delivery station; at least one cylinder support including spaced side members intermediate the feeder and delivery stations; a plate cylinder journaled between the side members; a printing plate on the plate cylinder; a blanket cylinder journaled between the side members, said blanket cylinder having an axially extending gap formed in the periphery thereof; a blanket on the blanket cylinder in rotative contact with the plate; an impression cylinder adjacent the blanket cylinder, said impression cylinder having an axially extending gap formed in the periphery thereof; means to rotate the said cylinders; means for applying ink to the printing plate; continuous flexible conveyors movably extending in a smooth uninterrupted path along each side of the press from the feeder station through the nip formed by the blanket cylinder and impression cylinder to the delivery station; spaced gripper bars extending between the conveyors and movable from the feeder station to the delivery station; means to secure the gripper bars to the flexible conveyors adjacent the ends of the gripper bars; gripper means on said gripper bars adapted to receive and grip the leading edge of a sheet at the feeder station and continuously convey same between surfaces of the blanket cylinder and impression cylinder to the delivery station; and means to synchronize the movement of the blanket cylinder and impression cylinder and the gripper bars to cause the axially extending gaps in the blanket and impression cylinders and the gripper bars to be simultaneously moved into coinciding relationship relative to each other as the blanket and impression cylinders rotate, and the gripper bars being so spaced that the gripper bars enter the axially extending gaps and move between the blanket and impression cylinders in non-driving relationship with said blanket and impression cylinders.
 3. In a sheet-fed printing press, a feeder station; a delivery station; at least one cylinder support, including spaced side members intermediate the feeder and delivery stations; a printing cylinder journaled between the side members; an impression cylinder adjacent the printing cylinder, at least one of said cylinders having a gap formed therein; means to rotate the said cylinders; means for applying ink to the printing cylinder; flexible conveyors movably extending along each side of the press from the feeder station to the delivery station; spaced elongated sheet engaging means extending between the conveyors and movable from the feeder station to the delivery station, said sheet engaging means being adapted to engage a sheet at the feeder station and continuously convey same between the surfaces of the printing and impression cylinders to the delivery station; means to secure the sheet engaging means to the flexible conveyors adjacent the ends of the sheet engaging means; and means to synchronize the rotation of the cylinders and the sheet engaging means to cause the gap and the sheet engaging means to be simultaneously moved into coinciding relationship relative to each other as the cylinders rotate, and the sheet engaging means being so spaced that they enter the gap and move between the printing and impression cylinders in non-engaging relationship therewith.
 4. The combination called for in claim 3 wherein the impression cylinder is a second printing cylinder.
 5. The combination called for in claim 2 wherein the conveyors are continuous flexible members; aligned pairs of guide members adjacent opposite ends of the press about which the flexible members extend; and power means for driving said flexible members.
 6. The combination called for in claim 3 wherein the flexible conveyors are flat tapes.
 7. The combination called for in claim 2 with the addition of guide means at the ends of the gripper bars and extending longitudinally of said press for supporting and guiding said gripper bars, said guide means being positioned to guide the gripper bars along a substantially straight path.
 8. The combination called for in claim 7 wherein the guide means includes tracks, at least one said track extending along each side of the press; and guide members, each gripper bar having at least one said guide member mounted at each end thereof movably engaged with said track.
 9. The combination called for in claim 8 wherein the guide members are rollers.
 10. The combination called for in claim 8 with the addition of a rail along at least one of said tracks; and a guide surface on at least one of the guide members adapted to engage the rail of the track to provide lateral alignment for said bar.
 11. In a sheet-fed printing press, a feeder station; a delivery station; at least one cylinder support, including spaced side members intermediate feeder and delivery stations; a plate cylinder journaled between the side members; a printing plate on the plate cylinder; a blanket cylinder journaled between the side members, said blanket cylinder having a gap formed therein; a blanket on the blanket cylinder in rotative contact with the plate; an impression cylinder adjacent the blanket cylinder, said impression cylinder having a gap formed therein; means to rotate the said cylinders; means for applying ink to the printing plate; continuous flat, flexible tapes movably extending along each side of the press from the feeder station to the delivery station; aligned pairs of guide members adjacent opposite ends of the press about which the tapes extend; power means for driving said tapes; spaced gripper bars extending between the tapes and movable from the feeder station to the delivery station, each of said gripper bars comprising a support bar extending between said tapes, a plurality of spaced back-up plate supports rigidly connected to said support bar, a back-up plate rigidly secured to each said back-up plate support, an actuator shaft rotatably journaled in said back-up plate supports, gripper fingers secured to said actuator shaft, resilient means connected between the said actuator shaft and the back-up plate supports for rotating the actuator shaft urging the gripper fingers on the actuator shaft toward the back-up plate to receive and grip the leading edge of a sheet at the feeder station and continuously convey same between surfaces of the blanket cylinder and impression cylinder to the delivery station; means to secure the gripper bars to the tapes adjacent the ends of the gripper bars; and means to synchronize the rotation of the cylinders to cause the gap in the blanket cylinder and the gap in the impression cylinder to be simultaneously moved into coinciding relationship to each other as the cylinders rotate, and the gripper bars being so spaced and synchronized with relation to the cylinder that the gripper bars enter the coinciding gaps and move between the blanket and impression cylinders without engaging said blanket and impression cylinders.
 12. The combination called for in claim 11 with the addition of a cam follower connected to said actuator shaft; and a cam secured to said guide members, said follower and cam being positioned such that interaction between the cam follower and the cam will rotate the actuator shaft to pivot the gripper fingers away from the back-up plate.
 13. A printing press comprising, spaced aligned sheet transfer carrier guide members adjacent each end of the press; continuous flexible sheet transfer carriers extending about the carrier guide members at each side of the press; means to drive the carriers; a plurality of spaced gripper bars secured adjacent opposite ends of said bars to said carriers; at least one gripper member mounted on each gripper bar for gripping the edge of a sheet; carrier guide means secured to sides of the press guidably supporting the carriers, said gUide means having uninterrupted guide surfaces arranged to direct the gripper bars from one end of the press to the other along a path having no abrupt changes in direction such that dynamic forces transferred by a gripper bar to the carriers as a gripper bar is moved longitudinally from one end of the press to the other is substantially constant; cylinder supports at each side of the press; a printing cylinder extending between said supports and having ends rotatably supported thereby; an impression cylinder adjacent the printing cylinder to urge the sheet into pressure contact with the printing cylinder, at least one of said cylinders having a gap formed therein to allow passage of gripper bars between said cylinders such that tension in the said carriers is unchanged as each gripper bar moves toward, through, and out of said gap; means to actuate the gripper members to engage the edge of the sheet at one end of the press; and means to actuate the gripper members to release the sheet at the other end of the press.
 14. A printing press comprising, spaced aligned sheet transfer carrier guide members rotatably journaled adjacent each end of the press; means to drive at least one of the guide members; continuous flexible sheet transfer carriers extending about the carrier guide members at each side of the press and being rotatable with the guide members; indexing means mounted in spaced apart peripheral relation on at least one of the guide members; surfaces spaced longitudinally of the carriers engageable with the indexing means; a plurality of spaced gripper bars secured adjacent opposite ends of said bars to said carriers; at least one gripper member mounted on each gripper bar for gripping the edge of a sheet; carrier guide means secured to sides of the press guidably supporting the carriers, said guide means having uninterrupted guide surfaces arranged to direct the gripper bars from one end of the press to the other along a path having no abrupt changes in direction such that dynamic forces transferred by a gripper bar to the carriers as a gripper bar is moved longitudinally from one end of the press to the other is substantially constant; cylinder supports at each side of the press; a printing cylinder extending between said supports and having ends rotatably supported thereby; an impression cylinder adjacent the printing cylinder to urge the sheet into pressure contact with the printing cylinder, at least one of said cylinders having a gap formed therein to allow passage of gripper bars between said cylinders such that tension in the said carriers is unchanged as each gripper bar moves toward, through, and out of said gap; means to actuate the gripper members to engage an edge of the sheet at one end of the press; means to actuate the gripper members to release the sheet at the other end of the press; and synchronizing means connected between the printing cylinder and the guide members to cause same to move in a selected unchanging speed relationship.
 15. A printing press comprising, spaced aligned sheet transfer carrier guide members rotatably journaled adjacent each side of the press; continuous flexible sheet transfer carriers extending about the carrier guide members at each side of the press; slotted blocks mounted in spaced apart peripheral relationship on the guide members; a plurality of spaced gripper bars secured adjacent opposite ends of said bars to said carriers; surfaces on each of the gripper bars engageable with the slots in the blocks to cause the carriers to rotate with the guide members; at least one gripper mounted on each gripper bar for gripping the leading edge of a sheet; cylinder supports at each side of the press; a printing cylinder extending between said supports and having ends rotatably supported thereby; an impression cylinder adjacent the printing cylinder to urge the sheet into the pressure contact with the printing cylinder; means on the press and engageable with the gripper bars to cause said gripper bars to move in a straight path thrOugh the nip formed by adjacent surfaces of the printing cylinder and the impression cylinder; means to actuate the gripper members to engage the leading edge of the sheet at one end of the press; and means to actuate the gripper members to release the sheet at the other end of the press.
 16. The combination called for in claim 15 with the addition of means for adjusting the peripheral position of each slotted block relative to the guide member, wherein each guide member is a tape wheel.
 17. The combination called for in claim 16 wherein the means for adjusting the position of each slotted block includes holes in the tape wheel, elongated holes in the slotted block, bolts extending through the holes in the slotted blocks and the tape wheel, a support block rigidly connected to the tape wheel having a threaded hole therethrough, and an adjusting screw threadedly engaging the threaded hole in the support block extending therethrough to engage an edge of the slotted block.
 18. The combination called for in claim 17 with the addition of a key on the slotted block and a keyway in the tape wheel wherein the key extends into the keyway.
 19. The combination called for in claim 16 wherein each pair of wheels is rigidly connected to an axle, one of said axles being rotatably journaled at the opposite ends thereof at opposite sides of the press, axle hangers adjustably suspended from each side of the press, the other wheel axle being rotatably journaled at the opposite ends thereof in said hangers, and means mounted on opposite sides of the press for moving said hangers for adjusting tension in the flexible members.
 20. The combination called for in claim 19 wherein the means for moving the hangers includes a resilient member to absorb shock and to compensate for dimensional change of the flexible members.
 21. The combination called for in claim 20 wherein the means for moving the hangers comprises a collar rotatably journaled on the axle, an adjusting bolt pivotally connected to said collar, a stationary block rigidly connected to a side of the press, a movable block, resilient means securing said movable block to the stationary block, the adjusting bolt being secured to the movable block whereby the resilient means absorbs shock.
 22. The combination called for in claim 21 with the addition of an adjusting nut on said bolts, a hole in said movable block adapted to slideably engage the bolt, whereby adjustment of the nut on the bolt pivots the hanger to adjust tension in the flexible member.
 23. The combination called for in claim 1 wherein there are a plurality of cylinder supports with associated cylinders between the feeder and delivery stations, whereby a sheet is successively and continuously conveyed by the transfer means between the printing and impression cylinders in the supports.
 24. The combination called for in claim 23 wherein the cylinder support is adapted to maintain the tangent points between the printing and impression cylinders on a common plane.
 25. The combination called for in claim 24 wherein there is a cusp area on each side of the tangent points of the printing and impression cylinders in the supports and the transfer means and the sheet carried thereby substantially bisects the cusp areas upon passing between said cylinders.
 26. The combination called for in claim 1 wherein there are a plurality of cylinder supports with associated printing cylinders, and the drive means includes a motor mounted adjacent each support; independent power transmission means driven by each said motor and drivably connected to each printing cylinder and ink applying means; and synchronizing means connecting each transmission means to cause each printing cylinder to run at substantially the same surface speed.
 27. In a sheet fed printing press, a feeder station; a delivery station; a plurality of cylinder supports, each said support comprising spaced side members intermediate the feeder and delivery stations; a plate cylinder Journaled between the side members; a printing plate on the plate cylinder; a blanket cylinder journaled between the side members; a blanket on the blanket cylinder in rotative contact with the printing plate; an impression cylinder adjacent the blanket cylinder; means for applying ink to the printing plate; a motor mounted adjacent each cylinder support; independent power transmission means driven by each said motor and drivably connected to each plate cylinder, blanket cylinder and ink applying means; pivoted links connecting each independent power transmission means, said links being operably connected to and extending between the blanket cylinders of adjacent cylinder supports to cause said blanket cylinders to rotate at substantially the same speed; continuous sheet transfer means movably extending from the feeder station to the delivery station; gripper means carried by the sheet transfer means adapted to receive and grip the leading edge of a sheet at the feeder station and continuously convey same along a substantially straight path between the surfaces of the blanket cylinder and impression cylinder to the delivery station.
 28. In a sheet-fed printing press, a feeder station; a delivery station; a plurality of cylinder supports, each of said supports including spaced side members intermediate the feeder and delivery stations; upper and lower plate cylinders journaled between the side members; a printing plate on at least one of said plate cylinders; upper and lower blanket cylinders journaled between the side members; a blanket on at least one of said blanket cylinders in rotative contact with one of the printing plates; upper and lower plate cylinder gears connected to the upper and lower plate cylinders, upper and lower blanket cylinder gears connected to the blanket cylinders, the upper plate cylinder gear and upper blanket cylinder gear being in meshing relation, and the lower blanket cylinder gear and the lower plate cylinder gear being in meshing relation; first and second idler gears rotatably journaled on a side frame in meshing relation with each other and each of said idler gears being in meshing relation with at least one of said plate cylinder gears; separate motors adjacent each cylinder support to rotate the gears; synchronizing means connecting gears on adjacent supports; means for applying ink to the printing plate; continuous sheet transfer means movably extending from the feeder station to the delivery station; gripper means carried by the sheet transfer means adapted to receive and grip the leading edge of a sheet at the feeder station and continuously convey same along a substantially straight path between the surfaces of adjacent blanket cylinders to the delivery station.
 29. The combination called for in claim 28 wherein the synchronizing means comprises, a crankplate secured to each idler gear, a crankpin extending outwardly from each crankplate, and links rotatably journaled on each crankpin wherein a first link connects crankpins on the first idler gear of each support and a second link connects crankpins on the second idler gear of each support; said links being positioned to cause the plate cylinders and blanket cylinders to rotate at equal surface speeds.
 30. The combination called for in claim 29 with the addition of third and fourth idler gears rotatably journaled on a drive-side side frame, an axle rotatably journaled at the opposite ends thereof in the side frames, spaced tape wheels fixedly secured to said axle, a tape wheel gear fixedly secured to said axle, a drive gear rigidly connected to the fourth idler gear in meshing relation with the tape wheel gear, crankplates adjustably secured to each of said third and fourth gears, crankpins extending outwardly from each crankplate, a link connecting the crankpins on the first and third idler gears and a second link connecting the second and fourth idler gears, thereby synchronizing the speed of the tape wheels and each printing tower motor.
 31. The combination called for in claim 30 with the addition of swing grippers in the feeder station, a cam rigidly connected to the fourth idler gear, and a linkage adapted to be operated by said cam to provide power to the swing grippers.
 32. In a sheet-fed printing press, at least one cylinder support, including spaced side members; a plate cylinder journaled between the side members; a printing plate on the plate cylinder; a blanket cylinder journaled between the side members; a blanket on the blanket cylinder in rotative concept with the plate; an impression cylinder adjacent the blanket cylinder, said blanket cylinder and said impression cylinder being positioned to form cusp areas on opposite sides of the tangent points thereof; a gap formed in at least one of said cylinders; means for applying ink to the plate; continuous flexible sheet conveyor members movably extending along opposite sides of the press; gripper members secured to the conveyor members adapted to receive and continuously grip the edge of a sheet and convey same into the cusp area on one side of the blanket and impression cylinders, between the blanket and impression cylinders, and through the cusp area on the other side of the blanket and impression cylinders; guide means on the press arranged to control the direction of travel of the gripper members and positioned to cause the gripper members to move along a path substantially bisecting the cusp areas between the blanket cylinder and the impression cylinder; and means to synchronize the movement of the cylinders and the gripper members to cause the gap in the cylinder and the gripper members to be simultaneously moved into coinciding relationship relative to each other as the cylinders rotate, and the gripper members being so spaced that the gripper members enter the gap and move between the blanket and impression cylinders in non-driving relationship with said blanket and impression cylinders.
 33. The combination called for in claim 32 wherein there are a plurality of supports and associated cylinders, and the flexible conveyors and grippers thereon are so positioned on the press as to continuously convey the sheet between the cusp areas on opposite sides of the blanket and impression cylinders in each support.
 34. The combination called for in claim 33 wherein the tangent points between the blanket and impression cylinders in the respective supports are on a common plane and the conveyor members move along said common plane to substantially bisect the cusp areas on opposite sides of the adjacent blanket and impression cylinders.
 35. The combination called for in claim 34 wherein the impression cylinders are second blanket cylinders with blankets thereon and with the addition of another plate cylinder in each support having a plate thereon in rotative contact with the blanket on the second blanket cylinder.
 36. In a sheet-fed printing press, cylinder supports on each side of the press; a pair of printing cylinders rotatably journaled in the supports forming a printing nip therebetween and adapted to print images on opposite sides of sheets passed through said nip, each of said printing cylinders having an axially extending gap formed in the periphery thereof; aligned tape wheels rotatably journaled adjacent opposite ends of the press; means to rotate the tape wheels; endless flat flexible tapes engaging said tape wheels and extending along opposite sides of the press, said tapes extending between said printing cylinders adjacent opposite ends thereof; gripper members adapted to receive and grip the edge of a sheet adjacent one end of the press and continuously convey same to other end of the press; means to secure the tapes to the gripper members adjacent opposite ends of the gripper members; guide means extending along opposite sides of the press to cause the gripper members to move in a substantially straight uninterrupted path through the printing nip from one end of the press to the other; means to rotate the printing cylinders; and means to synchronize the movement of the printing cylinders and the gripper members to cause the axially extending gaps in the printing cylinders and the gripper members to be simultaneously moved into coinciding relationship relative to each other as the cylinders rotate, and the gripper members being so spaced that the gripper members enter the axially extending gaps and move between the printing cylinders in non-driving relationship with said printing cylinders.
 37. The combination called for in claim 36 wherein each printing cylinder has a resilient surface.
 38. The combination called for in claim 36 wherein the means to rotate the tape wheels comprises coacting means operably connected to at least one of the printing cylinders and to at least one of the tape wheels, said coacting means being adapted to cause the tape wheel and the printing cylinder to rotate at a speed such that a sheet carried by the gripper means and the printing cylinders move at equal surface speeds.
 39. In a printing press, spaced cylinder supports positioned at each side of the press; at least one printing cylinder having ends rotatably secured to the supports, said printing cylinder having a relieved area formed therein extending along the length thereof and areas of reduced diameter adjacent each end of said printing cylinder; means adjacent the printing cylinder to urge a sheet into pressure engagement with the printing cylinder; drive means operably connected to the printing cylinder; drive members adjacent each side at each end of the press; endless flexible conveyors extending along each side of the press; means to drivingly secure the conveyors to the drive members adjacent opposite ends of the press; an elongated gripper member spanning the axial length of said printing cylinder, said gripper member being adapted to grip an edge of a sheet; means to secure the gripper member to the conveyors adjacent opposite ends of the gripper member; synchronizing means operably connected between the printing cylinder and at least one of the drive members to cause the gripper member and the relieved area in the printing cylinder to move at equal linear speeds, said relieved area being formed to allow the gripper member to move freely therethrough without engaging the gripper member, and said reduced diameter areas being formed to receive and allow free movement of the conveyors therethrough such that the linear velocity of the gripper member is substantially constant as it is moved by the conveyor from one end of the press to the other.
 40. The combination called for in claim 39 wherein the means to urge a sheet into pressure engagement with the printing cylinder is an impression cylinder having a relieved area formed therein extending longitudinally thereof and reduced diameter areas at each end portion thereof, said reduced diameter areas on the printing cylinder and the impression cylinder being positioned to form unobstructed openings between said cylinders at opposite ends thereof to receive the conveyors, said conveyors being arranged to move freely through said openings without driving engagement therewith.
 41. In a sheet-fed printing press the combination of, spaced side frames at each side of the press; a printing cylinder having ends rotatably secured to the side frames; an impression cylinder having ends rotatably secured to the side frames; the surfaces of said printing cylinder and said impression cylinder having substantially equal resilience; means for applying printing fluid to at least one of said surfaces; sheet transfer means in non-engaging relationship to the cylinder adapted to continuously grip a sheet and move same without interruption from one end of the press to the other; guide means at opposite sides of the press to direct the sheet transfer means between the printing cylinder and the impression cylinder; said cylinders having recessed areas formed therein, the recessed areas on each of said cylinders being positioned relative to recessed areas on the other of said cylinders to form an unobstructed passage between said cylinders; means adjacent an end of the press to move the sheet transfer means through said unobstructed passage between said cylinders, the sheet transfer means moving free of engagement with the cylinder; and means secured between the printing and impression cylinders and the means to move the sheet transfer means to cause same to move in a constantly registered relationship.
 42. The combination called for in claim 41 wherein the guide means comprises stationary tracks extending longitudinally of the press and adapted to guide the sheet transfer means along a substantially straight path from one end of the press to the other.
 43. In a sheet-fed printing press, a feeder station; a delivery station; at least one cylinder support, including spaced side members intermediate the feeder and delivery stations; a printing cylinder journaled between the side members; said printing cylinder having a gap formed therein; an impression cylinder adjacent the printing cylinder, said impression cylinder having a gap formed therein; means to rotate the said cylinders; means for applying ink to the printing cylinder; flexible conveyors movably extending along each side of the press from the feeder station to the delivery station; spaced elongated gripper bars extending between the conveyors and movable from the feeder station to the delivery station; means to secure the gripper bars to the flexible conveyors adjacent the ends of the gripper bars; gripper means on said gripper bars adapted to receive and grip the leading edge of a sheet at the feeder station and continuously convey same between the surfaces of the printing cylinder and impression cylinder to the delivery station; and means to synchronize the rotation of the cylinders to cause the gap in the printing cylinder and the gap in the impression cylinder to be simultaneously moved into coinciding relationship relative to each other as the cylinders rotate, and the gripper bars being so spaced that the gripper bars enter the coinciding gaps and move between the printing and impression cylinders in non-driving relationship with said printing and impression cylinders.
 44. In a sheet-fed printing press, a plurality of pairs of spaced cylinder supports at opposite sides of the press intermediate ends of the press; at least one printing cylinder rotatably secured between each pair of supports; an impression cylinder rotatably secured between each pair of supports to urge a sheet into pressure engagement with each printing cylinder, at least one of said cylinders having a gap formed therein; aligned drive members adjacent opposite ends of the press; flexible conveyors extending along opposite sides of the press in driven engagement with at least one of said drive members; stationary guide members secured relative to opposite sides of the press and extending in a substantially straight line from one end of the press to the other; sheet engaging means secured to the conveyors and arranged to engage said guide means, said sheet engaging means being adapted to engage the leading edge of a sheet; and means to rotate the drive members and cylinders to move the sheet engaging means at a constant velocity from one end of the press to the other; and means to synchronize movement of the gap in the cylinder and the sheet engaging means to cause the gap and the sheet engaging means to be simultaneously moved into coinciding relationship relative to each other as the cylinders rotate to pass the sheet engaging means through the gap in the cylinder in non-driving relationship therewith.
 45. In a sheet-fed printing press, a feeder station; a delivery station; cylinder support members at each side of the press; a printing cylinder journaled between the support members; an impression cylinder journaled between the support members; flexible conveyors movably extending along each side of the press; elongated sheet engaging elements axially aligned with saId cylinders; means to secure the sheet engaging elements to the flexible conveyors, said sheet engaging elements being adapted to carry a sheet; guide means adjacent each side of the press, said sheet engaging elements being movably engageable with said guide means; cylinder drive means to rotate the printing cylinder and the impression cylinder; conveyor drive means to move the flexible conveyors longitudinally of the press, said printing cylinder and said impression cylinder being adapted to pass the flexible conveyors and the sheet engaging elements therebetween in non-interengaging relationship to said cylinders; and synchronizing means between the cylinder drive means and the conveyor drive means arranged to cause the flexible conveyors and the cylinders to move at equal linear surface speeds as the conveyors move between said cylinders. 